Reactive Oxygen Species in Ni(II) Carcinogenesis

  • Shi, Xianglin (PI)

Grants and Contracts Details


Nickel-containing compounds are human carcinogens. The mechanisms of their carcinogenic actions remain to be investigated. Recent studies have indicated that reactive oxygen species (ROS) my play an important role. We hypothesize that nickel induces generation of ROS, which activate nuclear transcription factors, leading to cell transformation and tumorigenesis. Specific Aim 1 will detect and identify ROS generated in human bronchial epithelial (BEAS-2B) cells exposed to nickel compounds and investigate the mechanism involved. We hypothesize that nickel (Ni3S2 and NiCI2) can stimulate BEAS-2B cells to activate NADPH oxidase via cdc42 and p47phox to produce superoxide radical, which is then converted to hydrogen peroxide and hydroxyl radical. Specific Aim 2 will test the hypothesis that ROS are required for activation of NFAT and NFkappaB in BEAS-2B cells and in vivo in response to nickel compounds. The role of ROS in nickel-induced activation of NFAT and NFkappaB in BEAS-2B cells will be evaluated by co-transfection of NFkappaBluciferase or NFAT-Iuciferase reporter plasm ids and specific ROS scavenger enzymes. For in vivo study, BALB/c transgenic mice with alternation of antioxidant enzymes or NADPH oxidase (ROS generating enzyme) will be employed. Specific Aim 3 will Investigate the role of ROS, NFAT and NFkappaB in nickelinduced cell transformation and tumorigenesis. We hypothesize that ROS activate transcription factors and cause cell transformation and tumorigenesis. We will use overexpression of DN-NFAT, DN-lkappaBalpha and DN-IKKbeta to investigate the involvement of NFAT and NFkappaB in nickel-cell transformation and induced tumorigenesis. The role of ROS will be investigated using specific antioxidant enzyme expressions and NADPH oxidase alternation. We anticipate that nickel causes activation of NFAT and NFoB through ROS reactions, leading to cell transformation and tumorigenesis. We attempt to link the cell transformation and tumorigenesis with specific transcription factors and specific reactive oxygen species. The results obtained from this proposal will elucidate the role of ROS and NFAT/NFkappaB signaling in Ni compoundsinduced carcinogenesis. The long term goals are to provide a fundamental understanding concerning the mechanism of carcinogenic actions of Ni; to fill a need for the mechanistic information of cancer risk assessment for exposure; to propose methods for early detection; and to develop intervention and
Effective start/end date3/1/082/28/15


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